It provides a means for the pharmaceutical industry to make payments to the Government based on the growth of branded medicines.

Figures from the Department of Health show the Health and Social Care Board (HSCB) has received £47.7m to date. The figures were released after enquires by SDLP health spokesman Fearghal McKinney.

In Scotland, PPRS payments are going into a new medicines fund that covers treatments for rare and end-of-life conditions.

There are around 40 cancer drugs available to patients elsewhere in the UK that are not readily available in Northern Ireland. Mr McKinney said the "prohibitive system" should end.

In the past, the Department of Health has argued it would need a special cancer drugs fund, which isn't affordable. However, Mr McKinney believes the PPRS rebate should help bankroll the provision.

"Cancer patients in Northern Ireland have waited long enough for equal access to cancer drugs," he said.

"The Minister's concern over financial sustainability is easily negated if we look at the PPRS receipts received by the department. In fact, in the last two years, the Department of Health has received £50m for investment in innovative medicines."

A spokesman for the Department of Health said: "The Minister's priority is to ensure that the new access criteria for specialist drugs will provide a transparent and sustainable system for patients over the long term.

"The new criteria will be ready early in the new Assembly mandate and in the meantime access to cancer and other specialist drugs that are not routinely commissioned in Northern Ireland is available through the current IFR (Individual Funding Requests) process subject to approval by the HSCB.

"It has regularly been made clear to Mr McKinney and the health committee that the sum required for new drugs each year far exceeds that returned to Northern Ireland through the PPRS scheme."